As I've mentioned in previous blogarticles, my wife and I have
been working on driving an analog VU meter based on the sound going
out the Raspberry Pi's audio outputs. This now works!

Here's a video demonstrating the result:

The music [1] is playing from a Raspberry Pi, with software running
on the Pi digitally sampling the peak output audio level and writing
that out to an 8-bit digital-to-analog converter (DAC). The DAC
output is then used to drive the analog meter. If you're interesting
in knowing how all this hangs together, keep reading.